WASHINGTON » The Smithsonian’s National Museum of Natural History is acquiring its first full Tyrannosaurus rex skeleton for eventual display in a new dinosaur hall planned for the museum on the National Mall.

The museum announced Thursday that it reached a 50-year loan agreement with the Army Corps of Engineers to display one of the most complete T. rex specimens ever discovered. It’s known as the "Wankel T. rex."

The rare fossil was found in 1988 by rancher Kathy Wankel on federal land near the Fort Peck Reservoir in eastern Montana. Between 1990 and 2011 the fossil was loaned to the Museum of the Rockies in Bozeman, Mont.

The T. rex will be the centerpiece of a new dinosaur hall scheduled to open in 2019. Only a few museums display such nearly complete skeletons, most notably in New York City, Pittsburgh, Los Angeles and Chicago. But the Smithsonian has long wanted a T. Rex of its own for the natural history museum, which draws more than 7 million visitors yearly.

Museum Director Kirk Johnson, a paleontologist, said the world’s largest natural history museum and the world’s most famous dinosaur are finally coming together.

"It’s sort of a match made in heaven," he said. "It needed to be done a long time ago. We’ve done it now."

T. rex was one of the largest meat-eating animals to ever live on land. It weighed more than 5 tons and reached 40 feet in length. The dinosaur roamed across much of western North America between 66 million and 68 million years ago. Most fossils have been discovered in Montana, the Dakotas, Wyoming and Canada.

But Smithsonian field crews have never worked in those areas to dig to find a T. rex, Johnson said.

"It’s a rare animal," Johnson said. "Think about this: T. rex is sort of the most iconic of all dinosaurs, and to have a real one is like having the Hope Diamond."

The diamond and the new dinosaur specimen will likely be the must-see attractions at the museum in the future, he said. Previously, the Smithsonian only had plastic and plaster reproductions of a T. rex.

The Smithsonian is planning a temporary exhibition about the world of the T. rex next year before the permanent exhibit opens. This summer the museum is sending a team to North Dakota to collect fossils of other plants and animals that lived at the time of the T. rex, Johnson said, "to flesh out that world and bring that world back for our visitors."

On the Net » National Museum of Natural History: www.mnh.si.edu

–Brett Zongker / Associated Press